Multiple displays are great, but if you're using a laptop with LEDs alongside a monitor without LED backlighting your laptop display will outshine your desktop monitor—this disparity in brightness levels can cause eyestrain. Technology blog Unpluggd recommends turning down the brightness of all of your displays to match the dimmest monitor.

An easy way to enable this and also match your brightness levels to ambient light is using an application called F.lux, which we've covered in the past. With the amount of time most of us spend in front of displays these days, it is best to do all we can to prevent eyestrain.